1. Field of the Invention
The invention relates generally to the field of photography, and in particular to a film cartridge having coded means indicative of one or more film characteristics such as film speed.
2. Description of the Prior Art
It is well known for a 35 mm film cartridge to include coded means indicative of one or more film characteristics such as film speed. According to one example, the commercially available KODAK DX 35 mm film cartridge has a series of six patches or areas located on the outside of the cartridge shell. Patch no. 1 is conductive for every available film speed since it is intended to serve as a common area or ground for sensing by a corresponding electrical probe in a camera designed for use with the DX cartridge. Patches no. 2-6 are selectively conductive or non-conductive for sensing by respective electrical probes in the camera to provide binary encodements of respective film speeds as ISO speed values or the equivalent DIN speed values. An insulative paint covers those patches selected to be non-conductive to prevent them from being conductive. Further details of the DX cartridge are disclosed in U.S. Pat. No. 4,982, 209, issued Jan. 1, 1991.
Another example of a film cartridge with a film speed encodement is disclosed in U.S. Pat. No. 3,444,795, issued May 20, 1969. In this instance, the cartridge shell has a series of equally spaced locations each one of which either is notched or is not notched for sensing by mechanical probes in a camera to provide binary encodements of respective film speeds.